1. Field of the Invention
The present invention relates to a method, an apparatus and a medium thereof for eliminating noise from a voice signal, and more particularly, to a noise elimination method and apparatus that can eliminate noise in real time and without estimating a position of a speaker.
2. Description of the Related Art
Recently, indoor mobile robots have drawn a lot of attention due to the increased interests in health, safety, home networks, and entertainment. To such mobile robots, human-robot interaction (HRI) is essential. Generally, a mobile robot includes a microphone, a vision system, an ultrasonic sensor, an infrared sensor, and a laser sensor. Efficient interactions between human beings and the mobile robot can be realized only when the mobile robot recognizes human beings and perceives its surroundings using such devices.
A voice and sound input system included in a mobile robot is crucial to the free-roaming of the mobile robot as well as the HRI. However, the voice is attenuated by distance and deteriorated by environmental noises and reverberation. Various sources of noise and reverberations from walls or other objects are present in an indoor environment. In addition, more low-frequency components of voice are reduced with respect to distance than high-frequency components. In the indoor environment containing noise, a voice input system that enables a free-roaming mobile robot to recognize a user's voice from several meters away and identify the position of the user is required for HRI.
It should be possible to use the voice input system for voice recognition after voice enhancement and noise elimination. However, referring to FIG. 1, in an environment of a mobile robot 110, interference sources 130, such as a television or a radio producing sounds of music, coexist with a speaker 120, i.e., a voice source.
Also, since the mobile robot 110 including a microphone and the speaker 120 is not stationary, it is very difficult to use a conventional beam-forming method for voice recognition. Further, as it moves, the mobile robot 110 must accurately estimate the position of the speaker 120 and eliminate noise in real time. However, the estimation of the position of the speaker 120 by the mobile robot 110 using a multi-channel microphone is not accurate enough to guarantee the performance of a conventional beam-former.